Fire Effects on Vegetation: Towards a Process Model Linking Fire Behaviour, Plant Traits, and Plant Physiology
Abstract
Climate change is predicted to increase the frequency and intensity of fires as well as the length of the fire season. These changes in fire behaviour are expected to alter the composition, structure and functioning of plant communities. We are developing a process-based modeling framework for understanding and predicting climate change impacts on fire behaviour and vegetation response. The framework links a physics-based fire behaviour model (FIRETEC) with a trait-based plant physiological response model. FIRETEC solves equations for conservation of mass, momentum, energy, and chemical species to resolve fire behaviour through time and over complex terrain and fuel structures. The plant response model considers a number of fire injuries, including phloem and vascular cambium necrosis, xylem dysfunction (via air seed cavitation and conduit wall deformation), and foliage necrosis. These injuries are linked to whole-tree growth and mortality using a resource mass balance model. We present preliminary results for a coniferous forest subjected to a range of low intensity wildfires. Results suggest that post-fire tree mortality may occur as a result of either vascular cambium necrosis or xylem dysfunction. However, results also show that heat transfer into tree stems can cause substantial xylem dysfunction, even in the absence of complete cambium necrosis. This suggests that xylem dysfunction is a more fundamental mechanism of mortality than cambium necrosis (girdling). Ultimately, we demonstrate the applicability of physically-based models for predicting vegetation response to wildfire, and map fire behavior patterns of tree injury and mortality.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.B33G2549K
- Keywords:
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- 0428 Carbon cycling;
- BIOGEOSCIENCES;
- 0486 Soils/pedology;
- BIOGEOSCIENCES;
- 0496 Water quality;
- BIOGEOSCIENCES;
- 1807 Climate impacts;
- HYDROLOGY